/* XArrowAtom.java
 * =========================================================================
 * This file is part of the JLaTeXMath Library - http://forge.scilab.org/jlatexmath
 *
 * Copyright (C) 2009 DENIZET Calixte
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or (at
 * your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * A copy of the GNU General Public License can be found in the file
 * LICENSE.txt provided with the source distribution of this program (see
 * the META-INF directory in the source jar). This license can also be
 * found on the GNU website at http://www.gnu.org/licenses/gpl.html.
 *
 * If you did not receive a copy of the GNU General Public License along
 * with this program, contact the lead developer, or write to the Free
 * Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 * Linking this library statically or dynamically with other modules 
 * is making a combined work based on this library. Thus, the terms 
 * and conditions of the GNU General Public License cover the whole 
 * combination.
 * 
 * As a special exception, the copyright holders of this library give you 
 * permission to link this library with independent modules to produce 
 * an executable, regardless of the license terms of these independent 
 * modules, and to copy and distribute the resulting executable under terms 
 * of your choice, provided that you also meet, for each linked independent 
 * module, the terms and conditions of the license of that module. 
 * An independent module is a module which is not derived from or based 
 * on this library. If you modify this library, you may extend this exception 
 * to your version of the library, but you are not obliged to do so. 
 * If you do not wish to do so, delete this exception statement from your 
 * version.
 * 
 */

package org.scilab.forge.jlatexmath;

/**
 * An atom representing an extensible left or right arrow to handle xleftarrow and xrightarrow commands in LaTeX.
 */
public class XArrowAtom extends Atom {

    private Atom over, under;
    private boolean left;

    public XArrowAtom(Atom over, Atom under, boolean left) {
        this.over = over;
        this.under = under;
        this.left = left;
    }

    public Box createBox(TeXEnvironment env) {
        TeXFont tf = env.getTeXFont();
        int style = env.getStyle();
        Box O = over != null ? over.createBox(env.supStyle()) : new StrutBox(0, 0, 0, 0);
        Box U = under != null ? under.createBox(env.subStyle()) : new StrutBox(0, 0, 0, 0);
        Box oside = new SpaceAtom(TeXConstants.UNIT_EM, 1.5f, 0, 0).createBox(env.supStyle());
        Box uside = new SpaceAtom(TeXConstants.UNIT_EM, 1.5f, 0, 0).createBox(env.subStyle());
        Box sep = new SpaceAtom(TeXConstants.UNIT_MU, 0, 2f, 0).createBox(env);
        float width = Math.max(O.getWidth() + 2 * oside.getWidth(), U.getWidth() + 2 * uside.getWidth());
        Box arrow = XLeftRightArrowFactory.create(left, env, width);

        Box ohb = new HorizontalBox(O, width, TeXConstants.ALIGN_CENTER);
        Box uhb = new HorizontalBox(U, width, TeXConstants.ALIGN_CENTER);

        VerticalBox vb = new VerticalBox();
        vb.add(ohb);
        vb.add(sep);
        vb.add(arrow);
        vb.add(sep);
        vb.add(uhb);

        float h = vb.getHeight() + vb.getDepth();
        float d = sep.getHeight() + sep.getDepth() + uhb.getHeight() + uhb.getDepth();
        vb.setDepth(d);
        vb.setHeight(h - d);

        HorizontalBox hb = new HorizontalBox(vb, vb.getWidth() + 2 * sep.getHeight(), TeXConstants.ALIGN_CENTER);
        return hb;
    }
}
